Hydride generation system

ABSTRACT

The present disclosure is directed to a system and a method for hydride generation. In some embodiments, the system includes an assembly for introducing hydride generation reagents into a mixing path or mixing container, where the assembly includes first chamber configured to contain a first hydride generation reagent and a second chamber configured to contain a second hydride generation reagent. A first plunger is configured to translate within the first chamber and cause a displacement of the first hydride generation reagent, and a second plunger is configured to translate within the second chamber and cause a displacement of the second hydride generation reagent. The assembly further includes base coupling the first plunger and the second plunger together.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 15/688,396, filed Aug. 28, 2017, and titled “HYDRIDE GENERATIONSYSTEM.” now U.S. Pat. No. 10,340,832, which in turn is a divisional ofU.S. patent application Ser. No. 14/635,887, filed Mar. 2, 2015, andtitled “HYDRIDE GENERATION SYSTEM.” now U.S. Pat. No. 9,752,987, whichin turn claims priority under 35 U.S.C. § 119(e) to U.S. ProvisionalApplication Ser. No. 61/946,336, filed Feb. 28, 2014 and titled “HYDRIDEGENERATION SYSTEM.” U.S. patent application Ser. Nos. 15/688,396 and14/635,887 and U.S. Provisional Application Ser. No. 61/946,336 areherein incorporated by reference in their entireties.

BACKGROUND

Inductively Coupled Plasma (ICP) spectrometry is an analysis techniquecommonly used for the determination of trace element concentrations andisotope ratios in liquid samples. ICP spectrometry employselectromagnetically generated partially ionized argon plasma whichreaches a temperature of approximately 7,000K. When a sample isintroduced to the plasma, the high temperature causes sample atoms tobecome ionized or emit light. Since each chemical element produces acharacteristic mass or emission spectrum, measuring the spectra of theemitted mass or light allows the determination of the elementalcomposition of the original sample.

Sample introduction systems may be employed to introduce the liquidsamples into the ICP spectrometry instrumentation (e.g., an InductivelyCoupled Plasma Mass Spectrometer (ICP/ICP-MS), an Inductively CoupledPlasma Atomic Emission Spectrometer (ICP-AES), or the like) foranalysis. For example, a sample introduction system may withdraw analiquot of a liquid sample from a container and thereafter transport thealiquot to a nebulizer that converts the aliquot into a polydisperseaerosol suitable for ionization in plasma by the ICP spectrometryinstrumentation. Prior or during transportation of the aliquot to thenebulizer, the sample aliquot may be mixed with hydride generationreagents and fed into a hydride gas/liquid separator that channelshydride and/or sample gas into the nebulizer. The aerosol generated bythe nebulizer is then sorted in a spray chamber to remove the largeraerosol particles. Upon leaving the spray chamber, the aerosol isintroduced into the plasma by a plasma torch assembly of the ICP-MS orICP-AES instruments for analysis.

SUMMARY

Systems and methods for hydride generation are described herein. In someembodiments, a system includes an assembly for introducing hydridegeneration reagents into a mixing path or mixing container, where theassembly includes first chamber configured to contain a first hydridegeneration reagent and a second chamber configured to contain a secondhydride generation reagent. A first plunger is configured to translatewithin the first chamber and cause a displacement of the first hydridegeneration reagent, and a second plunger is configured to translatewithin the second chamber and cause a displacement of the second hydridegeneration reagent. The assembly further includes a base coupling thefirst plunger and the second plunger together.

A method of introducing hydride reagents into a mixing path or a mixingcontainer can include: depositing a first hydride generation reagent ina first chamber; depositing a second hydride generation reagent in asecond chamber that is rigidly connected with the first chamber;actuating the first and second chambers or a base coupled to a firstplunger and a second plunger, thereby causing the first plunger totranslate within the first chamber and the second plunger to translatewithin the second chamber to simultaneously output selected amounts ofthe first hydride generation reagent and the second hydride generationreagent.

A sampling system is also disclosed herein. In some embodiments, thesampling system includes a sampling assembly configured to draw a sampleinto a mixing path and a hydride generation assembly configured tointroduce selected amounts of a first hydride generation reagent and asecond hydride generation reagent into the mixing path. In someembodiments, the hydride generation assembly includes a first chamberconfigured to contain the first hydride generation reagent and a secondchamber configured to contain the second hydride generation reagent. Afirst plunger is configured to translate within the first chamber andcause a displacement of the first hydride generation reagent, and asecond plunger configured to translate within the second chamber andcause a displacement of the second hydride generation reagent. The firstplunger and the second plunger are coupled to a common base. Thesampling system may further include a nebulizer fluidically coupled withthe mixing path. The nebulizer can be configured to introduce at least aportion of the sample received from the mixing path into a spraychamber. For example, the nebulizer may introduce an aerosol includingat least a portion of the sample into the spray chamber. The spraychamber can then direct at least a portion of the aerosol that includesthe sample (e.g., fine aerosol particles) to an analysis site (e.g.,torch or plasma site) of a sample analysis instrument. For example, thespray chamber may be fluidically coupled with or form a portion of anICP spectrometry instrument, such as an ICP-MS, ICP-AES, or the like.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

DRAWINGS

The Detailed Description is described with reference to the accompanyingfigures. Any dimensions included in the accompanying figures areprovided by way of example only and are not meant to limit the presentdisclosure.

FIG. 1 is an isometric view of a hydride generation assembly,illustrated in accordance with an embodiment of this disclosure.

FIG. 2 is an exploded view of a hydride generation assembly, illustratedin accordance with an embodiment of this disclosure.

FIG. 3 is a cross-sectional view of a hydride generation assembly,illustrated in accordance with an embodiment of this disclosure.

FIG. 4 is a cross-sectional view of a plurality of plungers coupled to abase of hydride generation assembly, illustrated in accordance with anembodiment of this disclosure.

FIG. 5 is a schematic of an automated sampling system, illustrated inaccordance with an embodiment of this disclosure.

FIG. 6 is a flow chart showing a method of dispensing hydride generationreagents with a hydride generation assembly, such as the hydridegeneration assembly illustrated in one of FIGS. 1 through 4 or the like.

DETAILED DESCRIPTION

Overview

Sample introduction systems may be employed to introduce the liquidsamples into an analysis instrument, such as an ICP spectrometer (e.g.,ICP-MS, ICP-OES or ICP-AES), or the like. For example, a sampleintroduction system may withdraw an aliquot of a liquid sample from acontainer and thereafter transport the aliquot to a nebulizer thatconverts the aliquot into a polydisperse aerosol suitable for ionizationin plasma by ICP spectrometry instrumentation. Prior or duringtransportation of the aliquot to the nebulizer, the sample aliquot maybe mixed with hydride generation reagents and fed into a hydridegas/liquid separator that channels hydride and/or sample gas into thenebulizer. This can significantly increase sensitivity tohydride-forming reagents.

In some sampling systems, hydride generation reagents (e.g., HCL andNaBH₄) can be withdrawn from respective containers using high-precisionpumps, such as peristaltic pumps, and directed into a mixing path wherethey are mixed with the sample aliquot. However, peristaltic pumps mustbe carefully calibrated and synchronized to achieve simultaneousintroduction of the hydride generation reagents in required amounts.Moreover, peristaltic pumps consume a relatively large area and/orvolume, require tubing from the container to the pumps, tubing throughthe pumps, and tubing from the pump to the mixing path. Aside from thenecessary resources and associated costs, the length of the path thereagents must travel before reaching the mixing path can increase therisk of contamination.

The present disclosure describes a hydride generation assembly thatenables synchronized, simultaneous dispensing of hydride generationreagents from respective chambers by simultaneously actuating thechambers or a base coupling plungers that are configured to translatewithin the chambers. Accordingly, the hydride generation reagents can befed directly from their respective holding chambers through tubesleading to the mixing path. This may greatly reduce the risk ofcontamination and can allow for a smaller device packaging, which may beattractive in a laboratory setting where space is limited. In someembodiments, the hydride generation assembly can include one or moreadditional chambers for a carrier solutions, internal standards, and anyother fluids that can be simultaneously dispensed with the hydridegeneration reagents.

Example Implementations

FIGS. 1 through 4, illustrate a system 100 configured to generatehydrides in accordance with various embodiments of this disclosure.Those skilled in the art will appreciate that the embodimentsillustrated in the drawings and/or described herein may be fully orpartially combined to result in additional embodiments. Accordingly, theillustrated and described embodiments should be understood asexplanatory and not as limitations of the present disclosure.

A hydride generation system 100 (sometimes referred to herein as a“hydride generation assembly 100”) is shown in FIGS. 1 and 2. In someembodiments, two or more chambers 102 are coupled together (e.g.,rigidly connected with one another) or formed in a common (e.g.,monolithic) structure. For example, a first chamber and a second chambercan be formed from a single plastic mold, resulting in a commonstructure 102 that includes the first and second chambers, and in someembodiments, further includes one or more additional chambers. Thechambers 102 may include respective outlets 108, the outlets 108 beingconfigured for fluidically connecting the chambers 102 to a mixing pathor a mixing container where the respective fluids can be simultaneouslyintroduced. In some embodiments, the chambers 102 may include two ormore mounting members 105 that enable the chambers 102 to be rigidlyaffixed to a rigid structure (e.g., a stationary structure or anactuatable structure). In some embodiments, the mounting members 105 maycomprise holes configured to receive pins, screws, bolts, or otherfasteners that hold the chambers 102 in firm contact with the rigidstructure. The system 100 further includes two or more plungers 106 anda base 104 coupling the plungers 106 together. The base 104 may alsoinclude one or more mounting members that enable the base to be rigidlyaffixed to a rigid structure that may also be stationary or actuatable.

In FIG. 3, an embodiment of the system 100 is shown to include anassembly of rigidly connected or monolithic chambers 102 including atleast a first chamber 112 and a second chamber 114. The first chamber112 and the second chamber 114 may be configured to contain hydridegeneration reagents. For example, the first chamber 112 may include anHCL solution, and the second chamber 114 may include a NaBH₄ solution,or the first and second chambers 112 and 114 may be configured to holdany other combination of hydride generation reagents (e.g., HCL andSnCl₂). In some embodiments, the system further includes one or moreadditional chambers. For example, the system 100 may include a thirdchamber 116 for a carrier solution, an internal standard solution, orany other fluid that can be simultaneously dispensed with the hydridegeneration reagents. The number of chambers and respective plungers mayvary with different implementations of the system 100. For example, thesystem 100 may include two chambers (e.g., chamber 112 and chamber 114)and two plungers 106 coupled to the base 104, three chambers (e.g.,chambers 112, 114, and 116) and three plungers 106, four chambers andfour plungers, and so forth.

Each chamber (e.g., chamber 112, 114, or 116) includes at least twoports, an input 110 for receiving the respective plunger 106 and anoutput 108 for dispensing the fluid contained therein. In someembodiments, the output 108 is configured to connect with a tube orjoint that fluidically couples the output 108 to a mixing path or amixing container. In some embodiments, a chamber (e.g., chamber 112,114, or 116) may be at least partially tapered and/or may include anarrow passage positioned before the output 108. The chambers and theplungers can be differently sized to facilitate different flow volumes.For example, the cross-sectional area (for a cross-section perpendicularto a direction of fluid movement) or diameter of the first chamber 112may be different from the cross-sectional area or diameter of the secondchamber 114 or the third chamber 116, and so on. By coupling theplungers 106 together with the base 104, fluid can be displaced withinthe chambers in a synchronized manner to generate hydrides and/orintroduce selected amounts of fluids simultaneously into a commoncontainer or path. Moreover, the ratio of a first dispensed fluid (e.g.,a first hydride generation reagent) to another dispensed fluid (e.g., asecond hydride generation reagent) is well controlled by appropriatelysizing the chambers. The synchronized motion of all the chambers 102 orall of the plungers 106 that are coupled to the base 104 causesdispensing of all associated fluids from chambers 102 in a synchronizedmanner with the fluid ratios held constant—of course, the concentrationof each fluid can be altered to achieve specified concentration ratios.The chambers 102, however, may be sized according to default,pre-determined concentrations of the first and second hydride generationreagents. In some embodiments, the first chamber 112 and the secondchamber 114 are sized appropriately to dispense the first hydridegeneration reagent and the second hydride generation reagent in a ratiosuitable for forming a hydride when mixed with a sample. Additionalchambers (e.g., the third chamber 116) can also be sized appropriatelyfor hydride generation. For example, the first chamber 112, the secondchamber 114, and the third chamber 116 may be sized appropriately tointroduce the first hydride generation reagent, the second hydridegeneration reagent, and the carrier solution into a mixing path ormixing container in appropriate amounts relative to one another toenable a sample within the mixing path or mixing container to interactwith the hydride generation reagents.

In some embodiments, the two or more plungers 106 are movably coupledwith the base 104. As shown in FIG. 4, for example, the plungers 106 arerotationally coupled to the base 104 with at least one pin 120 thatextends through at least a portion of the base 104. Each plunger 106 isenabled to align itself with respect to its corresponding chamber (e.g.,chamber 112, 114, or 116). In this regard, movement (e.g., tilting orwiggling) of the plungers 106 with respect to the base 104 can preventor minimize jamming of the plungers 106 in their respective chambers102. This can be used to account for manufacturing tolerance variationsin the chambers 102 and/or the plungers 106. However, it should be notedthat a pin connection between the plungers 106 and the base 104 isprovided by way of example only and is not meant to limit the presentdisclosure. In other embodiments, the plungers 106 can be movablycoupled with the base 104 using other connectors, such asball-and-socket connectors, resilient connectors (e.g., rubber orspring-loaded connectors), or the like.

An embodiment of a sampling system 200 is shown in FIG. 5. In someembodiments, the sampling system 200 includes a sampling assembly 202(e.g., an automated syringe) configured to draw a selected amount of asample into a mixing path 204 that may be defined by a network of tubes.In some embodiments, the sampling system 200 includes the hydridegeneration assembly 100 (also referred to as “system 100”), where thehydride generation assembly is configured to introduce selected amountsof a first hydride generation reagent and a second hydride generationreagent into the mixing path 204 via tubes (e.g., tubes 206 and 208)connected to respective ones of the chambers 102. For example, tube 206may be connected to the first chamber 112 and tube 208 may be connectedto the second chamber 114. In some embodiments, the hydride generationassembly is further configured to introduce a selected amount of a thirdfluid, such as a carrier solution or internal standard, into the mixingpath 204 via a respective tube (e.g., tube 210) connected to arespective one of the chambers 102. For example, tube 210 may beconnected the third chamber 116. Those skilled in the art will furtherappreciate that the hydride generation assembly 100 may further includea fourth chamber for introducing a fourth fluid into the mixing path oranother fluid pathway, and so forth. A variety of changes can be madewithout departing from the scope of the present disclosure.

The sampling system 200 may further include a nebulizer 214 fluidicallycoupled with the mixing path 204. In some embodiments, a gas/liquidseparator 212 is positioned between the mixing path 204 and thenebulizer 214. In the gas/liquid separator 212, gaseous substancesformed by an interaction of the fluids in the mixing path 204 may beseparated from liquid substances to remove liquids before entering thenebulizer 214. In some embodiments, the removed liquids may be pumpedout of the separator 212 into a waste receptacle 222 via a peristalticpump 220. The gaseous substances fed into the nebulizer 214 may includeat least a portion of the sample. For example, gases in the mixing path204 may include one or more gaseous mixtures or compounds generated bythe sample and hydride generation reagents. After aerosolizing thereceived portions of the sample, the nebulizer 214 may be configured tointroduce the portion of the sample received from the mixing path 204into a spray chamber 216 that is either included within or coupled to ananalysis instrument 218, such as an ICP spectrometry instrument (e.g.,ICP-MS, ICP-OES, ICP-AES, or the like). The spray chamber 216 may beconfigured to direct at least a portion of the aerosol (e.g., fineaerosol particles) to an analysis site (e.g., torch or plasma site) of asample analysis instrument 218.

In some implementations, the plungers 106 are enabled to move while thechambers 102 are held stationary to displace fluid within the chambers102. For example, the base 104 may be driven an actuator 224 (e.g., anelectrical motor, linear actuator, or the like) while the chambers 102are mounted to a stationary structure. In other embodiments, thechambers 102 may be enabled to move while the plungers 106 are heldstationary to displace fluid within the chambers 102. For example, thebase 104 may be mounted to a stationary surface while a rigid structure(e.g., an armature or railing) coupled to the chambers 102 is moved byan actuator 224. In still further embodiments, both the plungers 106 andthe chambers 102 are moved to displace fluid within the chambers 102. Insome embodiments, the one or more actuators 224 are controlled by acontroller 226, such as a general-purpose computer (e.g., workstation),a specific-purpose computer, an ASIC, a programmable logic device, amicrocontroller, or the like. As used herein, the term “controller” caninclude electronic circuitry configured to perform a set of discreteoperations and/or a processor configured to execute program instructionsfrom a non-transitory storage medium (e.g., solid-state memory device,SD card, flash memory device, or the like). In some embodiments, thecontroller 226 is further configured to control valves, pumps, samplingassemblies, or other components of the sampling system 200.

Example Processes

FIG. 6 is a flow diagram illustrating a method 300 of simultaneouslyintroducing selected amounts of a first hydride generation reagent and asecond hydride generation reagent into a mixing path or a mixingcontainer. At step 302, a first hydride generation reagent (e.g., HCL)is deposited in a first chamber (e.g., chamber 112). At step 304, asecond hydride generation reagent (e.g., NaBH₄, SnCl₂, or the like) isdeposited in a second chamber (e.g., chamber 114) that is rigidlyconnected to the first chamber. Optionally, at step 306, a third fluid,such as a carrier solution or an internal standard, is deposited in athird chamber that is rigidly connected to the first and secondchambers. At step 308, either the assembly of chambers (e.g., chambers102) or a base that couples respective plungers (e.g., plungers 106) ofthe chambers is actuated to simultaneously dispense selected amounts ofthe respective fluids contained in the chambers. For example, theactuation of the assembly or the base may cause the first plunger totranslate within the first chamber and the second plunger to translatewithin the second chamber to simultaneously output selected amounts ofthe first hydride generation reagent and the second hydride generationreagent. This can also cause a third plunger to translate within thethird chamber to simultaneously output a selected amount of the carriersolution or any other fluid contained therein. As a result of thesynchronized fluid output, the hydride generation reagents and any otherfluids dispensed by the assembly of chambers are introduced into amixing path or a mixing container in fixed ratios with one another.

Those skilled in the art will appreciate that several of the steps ofmethod 300 may be performed in an alternative order than the orderillustrated in FIG. 6 or described herein. Some of the steps may beperformed simultaneously or at least partially overlapping in time.Furthermore, method 300 may include additional steps for carrying outany of the functions or operations described herein with regards tosystem 100 or system 200.

Although the subject matter has been described in language specific tostructural features and/or process operations, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

What is claimed is:
 1. A method, comprising: depositing a first hydridegeneration reagent in a first chamber; depositing a second hydridegeneration reagent in a second chamber that is rigidly connected withthe first chamber; actuating the first and second chambers or a basecoupled to a first plunger and a second plunger, thereby causing thefirst plunger to translate within the first chamber and the secondplunger to translate within the second chamber to simultaneously outputselected amounts of the first hydride generation reagent and the secondhydride generation reagent, wherein the first plunger and the secondplunger are rotationally coupled to the base, and a position of the basechanges relative to the first chamber due to translation of the firstplunger within the first chamber.
 2. The method of claim 1, furthercomprising: depositing a carrier solution in a third chamber, the thirdchamber being rigidly connected with the first chamber and the secondchamber, wherein actuating the chambers or the base further causes athird plunger to translate within the third chamber to simultaneouslyoutput a selected amount of the carrier solution with the selectedamounts of the first hydride generation reagent and the second hydridegeneration reagent.
 3. The method of claim 1, wherein the first plungerand the second plunger are coupled to the base with at least one pinthat extends through at least a portion of the base.
 4. The method ofclaim 1, wherein the first plunger is configured to align itself withthe first chamber and the second plunger is configured to align itselfwith the second chamber.
 5. The method of claim 1, wherein the firstplunger is configured to align itself with the first chamber and thesecond plunger is configured to align itself with the second chamber. 6.The method of claim 1, wherein the first plunger and the second plungerare coupled to the base using at least one of: ball-and-socketconnectors or resilient connectors.
 7. The method of claim 1, whereinthe first plunger and the second plunger are configured to move whilethe first chamber and the second chamber are held stationary.
 8. Themethod of claim 1, wherein the first plunger and the second plunger areheld stationary while the first chamber and the second chamber areconfigured to move.
 9. The method of claim 1, wherein one or moreactuators controlled by a controller actuate the first and secondchambers or the base coupled to the first plunger and the secondplunger.